The Role of Corneal Distortion in the Occurrence of Monocular Diplopia

Carney, Leo G.; Liubinas, Julius; Bowman, Kenneth J.

doi:10.1111/j.1755-3768.1981.tb02989.x

Cited by 19 publications

(3 citation statements)

References 7 publications

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“…The corneal distortions described by HOAs are responsible for the visual symptom of monocular diplopia, which has been reported after downward gaze reading. 1,18,[20][21][22][23][24]50 There is also evidence that the morphometry of the eyelids is associated with the induced corneal changes. In particular, the J45 astigmatic changes after the 40-degree tasks were correlated with the lower eyelid tilt.…”

Section: Discussionmentioning

confidence: 99%

“…[16][17][18] Corneal irregularity after reading has been linked to the visual symptom of vertical monocular diplopia. 1,[18][19][20][21][22][23][24][25] Using several clinical techniques, including keratometry and vision with pinholes and with rigid contact lenses, it has been established that monocular diplopia symptoms can be of corneal origin. These corneal changes can be accurately studied with the use of modern videokeratoscopes.…”

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confidence: 99%

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Corneal refractive changes due to short-term eyelid pressure in downward gaze

Shaw¹,

Collins²,

Davis³

et al. 2008

Journal of Cataract and Refractive Surgery

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The pressure of the eyelids on the cornea in short-term downward gaze resulted in optically and clinically relevant corneal changes. Correlation between the refractive corneal changes and eyelid parameters suggests that the angle, shape, and position of the eyelids influence the nature of the corneal changes. When high accuracy is required, refraction should be qualified by the visual tasks undertaken before assessment.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Corneal refractive changes due to short-term eyelid pressure in downward gaze

Shaw¹,

Collins²,

Davis³

et al. 2008

Journal of Cataract and Refractive Surgery

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show abstract

“…1 Predictably, in the absence of retinal or neural pathologies, the magnitude of blur is a principal determinant of vision quality. However, in addition to blur associated with defocus and aberrations, human observers occasionally report seeing multiple images monocularly, 2 most often reporting two images (diplopia), 3,4 but sometimes three (triplopia) [5][6][7] or more (polyplopia). 8,9 Conventional metrics of image quality based on the PSF and OTF were not designed to measure the effects of polyplopia, which has prompted us to explore the possibility that analysis of caustics in the PSF will reveal ways to predict the presence and number of multiple images to be expected, for an eye with known wavefront aberrations.…”

Section: Introductionmentioning

confidence: 99%

Catastrophe optics theory unveils the localised wave aberration features that generate ghost images

Barbero

Bradley

López‐Gil

et al. 2022

Ophthalmic Physiologic Optic

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Monocular polyplopia (ghost or multiple images) is a serious visual impediment for some people who report seeing two (diplopia), three (triplopia) or even more images. Polyplopia is expected to appear if the point spread function (PSF) has multiple intensity cores (a dense concentration of a large portion of the radiant flux contained in the PSF) relatively separated from each other, each of which contributes to a distinct image. We present a theory that assigns these multiple PSF cores to specific features of aberrated wavefronts, thereby accounting optically for the perceptual phenomenon of monocular polyplopia. The theory provides two major conclusions. First, the most likely event giving rise to multiple PSF cores is the presence of hyperbolic, or less probably elliptical, umbilic caustics (using the terminology of catastrophe optics). Second, those umbilic caustics formed on the retinal surface are associated with certain points of the wave aberration function, called cusps of Gauss, where the gradient of a curvature function vanishes. However, not all cusps of Gauss generate those umbilic caustics. We also provide necessary conditions for those cusps of Gauss to be fertile. To show the potential of this theoretical framework for understanding the nature and origin of polyplopia, we provide specific examples of ocular wave aberration functions that induce diplopia and triplopia. The polyplopia effects in these examples are illustrated by depicting the multi‐core PSFs and the convolved retinal images for clinical letter charts, both through computer simulations and through experimental recording using an adaptive optics set‐up. The number and location of cores in the PSF is thus a potentially useful metric for the existence and severity of polyplopia in spatial vision. These examples also help explain why physiological pupil constriction might reduce the incidence of ghosting and multiple images of daily objects that affect vision with dilated pupils. This mechanistic explanation suggests a possible role for optical phase‐masking as a clinical treatment for polyplopia and ghosting.

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Consequences of Monocular Diplopia for the Contrast Sensitivity Function

1996

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Though the human eye generally creates a single image on the retina, the literature contains many examples showing perceptual monocular diplopia. Previously, monocular diplopia resulting from astigmatic defocus has been demonstrated to cause a notch (local minimum) in the contrast sensitivity function (CSF). We examine Verhoeff's (1900) model which explains how monocular diplopia can occur through an interaction between defocus and common ocular aberrations. From the measured ocular transverse aberration function and from the measured monocular diplopia of three cyclopleged subjects we predicted multiple notches in the CSF with hyperopic spherical defocus. Monochromatic and polychromatic CSF were measured for vertical gratings with best refraction and with simulated myopia and hyperopia. Multiple notches in CSF were observed experimentally. Notches in the polychromatic CSF were smaller and broader than those found in the monochromatic CSF. Our aberration model was successful in predicting notches in the CSF with hyperopic spherical defocus. The implications for clinical measurement of CSF are discussed.

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The Role of Corneal Distortion in the Occurrence of Monocular Diplopia

Cited by 19 publications

References 7 publications

Corneal refractive changes due to short-term eyelid pressure in downward gaze

Corneal refractive changes due to short-term eyelid pressure in downward gaze

Catastrophe optics theory unveils the localised wave aberration features that generate ghost images

Consequences of Monocular Diplopia for the Contrast Sensitivity Function

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